Field of the Disclosure
The present disclosure relates to a test circuit capable of simultaneously detecting resistive open-circuit and short-circuit faults and analyzing TSV characteristics, and more particularly, to a TSV test circuit which may be included inside a TSV-based chip or in a separate external device.
Description of the Related Art
In a three-dimensional integrated circuit having a test structure capable of selecting a through-silicon via (TSV) with a resistive open-circuit or short-circuit fault, one method of characterizing a TSV is to measure a voltage that has passed through the TSV, calculate the resistance of the TSV, and then digitize the obtained result.
To measure a voltage that has passed through a TSV, a method of connecting the output voltage of the TSV to the input of a comparator and monitoring a section where output voltage transition of the comparator occurs while continuously changing the reference voltage of the comparator is used. The reference voltage value of the comparator at the time when the output voltage transition occurs corresponds to the voltage that has passed through the TSV.
A typical test structure for TSV testing consists of a comparator and a flip-flop, but this test structure can detect only TSV open-circuit faults. Otherwise, when both open-circuit and short-circuit faults are detected, these faults are sequentially tested, and thus test time can be increased in proportion to twice the number of through-silicon vias (TSVs) used in a three-dimensional stacked structure.
After a three-dimensional stacked structure has been formed in a three-dimensional integrated circuit, a test is required to inspect TSVs used in the circuit for a resistive open-circuit or short-circuit fault to determine whether the TSVs can function normally.
In addition to testing TSVs, common TSV analysis requires technologies to characterize TSVs and digitize the obtained results, which may be more important in the early stage of the mass production of a three-dimensional integrated circuit.
A typical test structure capable of analyzing TSV characteristics can detect only TSV open-circuit faults. Otherwise, when both open-circuit and short-circuit faults are detected, these faults are sequentially tested, and thus testing takes a lot of time. As a result, test time can be increased in proportion to twice the number of TSVs used in a three-dimensional stacked structure and test cost can be increased.